Apparatus for regulating combustion in furnaces.



No. 838,338. PATENTED DEC. 11, 1906.

I T. w. JOHNSON. APPARATUS FOR REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED JAN. 22. 1906.

2 SHEETS-SHEET 1.

No- 838,338. PATENTED DEO.11, 1906.

T. W. JOHNSON.

APPARATUS FOR REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED JAN. 22, 1906.

2 SHEETSSHEET 2.

rm om "UNITED STATES PATENT OFFICE.

APPAFIATUS FOR REGULATING COMBUSTION IN FURNACES. v

Specification of LettersjPatezit.

, application filed January 22. 1906. Seria1No. 297.358-

Patented. Dec. 11,1906.

To all whom it may concern:

Be it known that I, Tnotms W. JOHNSON,

a citizen of the United States, residing insuch combustion will at alltimes be effected under uniform or substantially uniform conditions,such conditions being dependent upon gas-pressure in thecombustion-chamber exerted against a normally constant counter-pressureand preferably against atmospheric pressure outside 'of the furnace; I

In the accompanying drawings, Figure 1 represents a steam-boiler furnaceprovided with one form of combustion-regulating apparatus in accordancewith my invention, and Fig. 2 illustrates another form of suchcombustion-regulating a paratus. I

Fig. 1 illustrates an or 'nary t e of boilerfurnace, 1 representing theclose ash-pit; 2, the pipe for supplying to said ash-pit air underpressure for supporting combustion; 3, the combustion-chamber; 4,thestack, and 5 I 1 the pivoted damper in said stack,'all of these partsbeing constructed in accordance with the present practice. 'Mounted atany available point upon a wall of the combustionchamber is a casing 6,which may be of any desired cross-sectional form and area, the

chamber 7 within this casing being in the present instance incommunication with the combustion-chamber of the furnace through a neck6", which passes through an opening 7 in. the rear wall of saidcombustion-chamber.

Wall of the casing.

Within the chamber 7 is a swinging-plate or diaphragm 8, which ispivoted adjacent to one wall of the casing 6, the pivot in theconstruction shown bein adjacent to the top his'diaphragm fits thecasing 6 as closely as is com atible with its free swinging movement, anas the casing 6 is open at the outer end the di hragm is exposed at alltimes on its outer aceto atmospheric pressure and on its inner face'tothe pressure maintained within the combustionchamber of the furnace.Hence as the latter pressure varies in respect to the normally fixedatmospheric pressure the diaphragm is caused to swing, and this swingingmove ment is utilized for the purpose of operating the mechanism 'forcontrolling the air- .for this air into or from the supply :or draft ofthe furnace, or both. 1 Many forms of mechanism may be utilized urpose.Hence it should be understood that the mechanism which I have shown inthe present instance is only for purposes of illustration and does notconstitute an essential part of my invention. Projecting from thepivot-spindle 9 of the diaphragm 8 is an arm 10, which operates the stem12 of a valve 13 for controlling the flow of water or other fluid underpressure to the lower portion of a damper-operating cylinder14, thelatter having a piston 15', with weighted rod 16, which is connected bya cord 17, assing over a ids-pulley 18, to a weig ted lever19 on t epivot-s indle of the stack-damper 5. Hence when t e piston 15 rises inthe cylinder 14 said damperis moved in one direction, and when the istondescends in the cylinder 14 the am or is moved in the oppositedirection, free ow, of

inder being permitte ow of fluid to .or from the lower. erid of thecylinder 14 therefore controls the movement of the piston therein andthe consequentoperationof the damper, the cutting off of such flowserving to lock the damper in the'position to which it had previouslybeen adjusted. The casing of the valve 13 has a fluid-inlet 20, afluid-out .let 21, and a pi e 22, leading to thecylinder 14,-and. thevave-stem 12 has two disks 23 and 24, the former constituting the governing element of the valve and the disk 24 being a pressure+equalizingdisk. A

When the disk 23 is in the upperFportion of the cyl- Y in Fi 1, itcloses the inlet en of the pipe 22,

and once locks the damper in the positionv previously assumed by-it,movement ofthe disk 23 in the -direction of the arrowmpljmitting flow offluid under pressure from the inlet-pipe 20 into the pipe 22, andtherefore to the cylinder 14, so as to raise the piston in.- the latter,while movement of the disk 23311. the direction of the arrom from theposition shown in Fig. Lopens, 't e connection between the i e 22,-andthe outletipe 21 and permits discharge of fluid from t e cylinder 14}and descent of the piston -therein.

The, parts are so arranged that when the p'ressuredn thecombustion-chamber is less than r'atmospheric pressure the diaphragm 8-,swinging inwardlyunder such atmos heric loo to the damper 5, therebychecking the draft until the pressure within the combustion- 4chamberagain equals or ap roaches atmospheric pressure and the iaphragm8 returns to its vertical and normal position. When, on the other hand,the pressure within the combustion-chamber 3 is. greater thanatmospheric pressure, the diaphragm 8 will swing outwardly, andthiswi-ll result in an opening of the damper 5, thereby providing afreer outflow from the combustion-chamher and lowering the-pressuretherein until it again equals or approaches atmospheric pressure andcausesthediaphragim to again assume its vertical and normal position.

It has been found in practice that the diaphragm 8 is so sensitive inits action that it is' affected by slight changes of pressure in thecombustion-chamber, and a condition'corre spondi-ng closely toatmospheric pressure is constantly maintainedin said combustionchamber,substantially uniform combustion being maintained at alltimesirrespective of variations in the depth or other conditions of thefuel-bed or in the pressure of the blast, the result being that when thefurnace-door is open there will, on the one hand, be no inflow of coldair to the combustion-chamber and, on the other hand, no outward blastof hot gases therefrom.

' In Fig. 2 I have illustrated my invention in connection with anelectromagnetic controlling device, the arm 10 of the swinging damperinthis case terminating in a switchfinger 10*, which vibrates between theopposite terminals 25 and'26 of an electric circuit containing twoelectromagnets 27 and 28,

rovided with a solenoid-core 29, the latter aving a cross-head 30, whoseopposite ends are contained between collars 31 on rods 32, suitablyguided on opposite sides of the magnets and normally maintained inmid-positionby means of up er and lower coiled sprin s33, interposedbetween the collars 31 and t e fixed guides 34 for the rods 32. Thelower ends of the rods 32 carry a cross-head 35, which is connected tothe stem 36 of a valve 37, the latter having an inlet 38 for water orother fluid under pressure, two outlets 39- and 40 communicating, resectively, with the up er and lower ends of a amper-op'erat ing cy inder14 and a discharge-outlet 41, communicating directly with one end of thevalve-chest 37 and through a pi e 42 with the opposite end of the same.he valvestem 36 has two disks 43 and 44, which normally close theoutlets 39 and 40 and cut off communication between the cylinder 14 andthe inlet-port 38 or discharge-port 41 0f the valve-chest. i

When the swinging diaphragm 8 occupies its normal or vertical position,the switchfinger 10 is free from contact with either of the terminals 25and 26.. Hence neither of the electromagnets27 or 2 8 is energizedfanjdthe solenoid-core 29 occupies a mid-position corresponding with thenormal or like position of the valve-disks 43 and 44. When, however, thediaphragm 8 swings outwardly, the switch-finger 10 is caused to contactwith the-terminal 25, the upper magnet 27' is en ergized, thesolenoid-core is raised, and corresponding movement is imparted to thevalve-stem 36, thereby opening the upper end of the cylinder 14 tothefluid-inlet 38 and the lower end of said cylinder to the fluid-outlet 41and causing a descent of the piston 15 in the cylinder and a movement ofthe stack-damper to increase the draft of the stack. When, on the otherhand, the diaphragm 8 swings inwardly, the switch-finger 10 is moved soas to contact with the terminal 26, the lower magnet 28is energized,

the solenoid-core 29 is depressed, and there is alike movement, of thevalve-stem36, so as to open communication between the lower end of thecylinder 14 and the fluid-inlet 38 and between the upper 'end of saidcylinder and the outlet 41, thus causing a rise of the piston 15 inthe'cylinder and a movement of the damper 5 to check the draft in thestack.

While I prefer in all cases to use the swinging diaphragm 8 because ofthe sensitiveness of the same, it will be evident that a flexiblediaphragm or a sliding piston might be used in place of the same, any ofthese devices -be ing intended to be covered by the term SSS ferred totherein, and instead of controlling the movement of the stack-damperalone the movements of said primary member may be caused to control adamper in the pipe 2, which supplies the air-blast to the closed ashpit.of the furnace, such a damper being illustrated at 46 in 2, or themovement of the primary member 8 may be transmitted both to thestack-damper and to a valve in the steam-pipe which supplies theblast-fan-driving en ine, such a valve being illustrated at 47in ig. 1,or either the blast-pipe damper or the engine-regulatingvalve may beused in connection with an open stack or with a stack having a normallyfixed damper, or my invention may be employed for regulating either theair-supply orstack-draft, or both, in a furnace having natural draftinstead of forced draft, what I consider to be the essentially novelfeature of my invention being the utilization of varying pressureswithin the combustion-chamber of the furnace for effecting controlv ofthe combustion.

Any normally fixed pressure, such as that i of a weight or a body ofwater .or other fluid acting against the primary element ofvtheregulating apparatus, may be employed in place of atmospheric pressureas the agent: opposed to the combustion-chamber pressure; butatmospheric pressure is preferred, as it dispenses with all means-forpreventing leakage and permits the use of the swinging diaphragm orother freely-moving body as the primary element.

No attempt has been made to show in the drawings the relativeproportions of the parts, as this would necessitate too small a scalefor some of them. 7

I claim' Y 1. Combustion-regulating apparatus for fiurnaces having aselements a regulating device actuated by fluid under pressure, a valvegoverning the operation of said device, and a swinging plate supportedso as to tend to re main in a neutral position under the action ofgravity and placed" to govern the movement of said valve, said platebeing acted upon in one direction by a normally fixed pressure and inthe other direction by the pressure in the combustion-chamber.

2. Combustion-regulating apparatus for furnaces having as elements aregulating device actuated by fluid under pressure, a balanced valvegoverning the operation of the same, and a swinging plate connected tosaid valve and supported so as to tend to maintain the valve in itsclosed position under the action of gravity, said plate being acted uponin one direction by atmospheric'pressure and i in the other direction bythe pressure in the combustion-chamber. I i

3. Combustion-regulating apparatus for furnaces having as elements aregulating device actuated by fluid uiider ressure, a valve governingthe operation 0 said device, a swinging plate su ported so as to tend toremain in a neutral position under the action of gravity, and providedwith a pair of contaots, a movable member connected to the plate andcoacting with said contacts, and electrical apparatus connected to thevalve so as togovern the operation of the same and included in thecircuit with said contacts, the plate being placed to be acted on in onedirection by a normally constant pressure and in the other direction bythe pressure in the combustion-chamber.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

THOS. w. JOHNSON.- Witnesses I 1 WALTER OHIsM, Jos. H. KLEIN.

